Opcache performance doc

Signed-off-by: Morris Jobke <hey@morrisjobke.de>

admin_manual/configuration_server/server_tuning.rst

@@ -72,3 +72,22 @@ Enable HTTP2 for faster loading
 -------------------------------
 
 HTTP2 has `huge speed improvements <https://www.troyhunt.com/i-wanna-go-fast-https-massive-speed-advantage/>`_ over HTTP with multiple request. Most `browsers already support HTTP2 over SSL (HTTPS) <http://caniuse.com/#feat=http2>`_. So refer to your server manual for guides on how to use HTTP2.
+
+.. _opcache:
+
+Enable PHP OPcache
+------------------
+
+The `OPcache <http://php.net/manual/en/intro.opcache.php>`_ improves the performance of PHP applications by caching precompiled bytecode. We recommend at least following settings:
+
+.. code:: ini
+
+  opcache.enable=On
+  opcache.enable_cli=1
+  opcache.interned_strings_buffer=8
+  opcache.max_accelerated_files=10000
+  opcache.memory_consumption=128
+  opcache.save_comments=1
+  opcache.revalidate_freq=1
+
+For more details check out the `official documentation <http://php.net/manual/en/opcache.configuration.php>`_ or `this blog post about some recommended settings <https://www.scalingphpbook.com/blog/2014/02/14/best-zend-opcache-settings.html>`_.

go.php

@@ -28,6 +28,7 @@ $mapping = array(
     'admin-backup'            => '/admin_manual/maintenance/backup.html',
     'admin-monitoring'        => '/admin_manual/operations/considerations_on_monitoring.html',
     'admin-sso'               => '/admin_manual/configuration_server/sso_configuration.html',
+    'admin-php-opcache'       => '/admin_manual/configuration_server/server_tuning.html#enable-php-opcache',
     
     'developer-code-integrity'=> '/developer_manual/app/code_signing.html',
     'developer-theming'       => '/developer_manual/core/theming.html',